Attachment means for aeronautical propellers



ATTACHMENT MEANS FOR AERONAUTICAL PROPELLERS I s. A. REED Feb.. 23, 1932.

Filed May 15, 1930 INVENTOR SILVA/V05 14. REED BY ATTORNEY STATES PATET .FFIGE SYLVANUS A. REED, OF NEW YORK, N. Y., ASSIGNOR T THE REED PROPELLER CO. ING, A. CORPORATION OF NEW] YORK ATTACHMENT MEANS FOR AERONAU'IIGAL PROPELLERS Application filed. May 15, 1930. Serial No. 452,562.

' My invention relates to aeronautical proj ellers, preferably of'metal, and 1s an 1mproveinent on the mountmg means described in my U. S. Patent #1,687,636, issued Octoher 1c, 1928.

In said issued patent I describe a metal aeronautical propeller made from a slab or plate or forging, of metal, preferably of strong aluminum alloy, and twisted continu- 19 ously in one angular direction from tip to tip Without reversal of twist. The propeller L .1 said patent, comprises means attached to the end of the engine drive shaft, said having crotches supporting and retaining the propellerin its appropriate p0- placed in the fork or bifurcation and is secured to the bent branches at propeller radii adapted to favorable support of the engine torque and of the propeller thrust. I thus eatly simplify the attachment of the proller to the engine shaft and efiect a large 5 in wei ht, complication and expense. also, if desired, reinforcing means to p a ent the shaft or crotch from splitting,

. distortion, or from other failure. Also, if

desired, other reinforcing means may be added to in re the stability of the propeller in its position Within the crotch.

in. Figs. 1, 2, 3, 4, and 5, I have illustrated preferred forms of my improvements. Figs. 1, 2. and 3, show the same propeller in three ciife3ent aspects. Fig. 1 is a side view, Fig. 2 a plan View, and Fig. 3 an end view of the central section cut off. Figs. 4 and 5 are enlarged views of certain details of construction.

Referring to Figs. 1, 2, and 3, in which the same numerals refer to the same features in all three views, 1 is a metal propeller, 2 and 3 are blades, ec is the central part, Z) is the come the trailing edge of blade 3'.

laterally in opposite directions, and then inwardly or outwardly to positions conforming each branch to the twist surface of the central part ac of 1.

8, 9 are bolt holes thru the branches the adjacent parts of 1.

The propeller 1 is cut, carved or forged to appropriate shape, and is then twisted continuously in the same angular direction from tip to tip, as'described in my U. S. patent aforesaid, so that the leading edge of blade 2 is carried over continuously to become the leading edge of blade 3, and the trailing edge of blade 2 is carried over continuously to be- Also, so that at the axial line b, the angle of the plate (from which the propeller is formed) to the plane ofrotation of the propeller is 90, and the angles at various radii of the propeller measured from b, are those appropriate to 5, 6 and the desired pitch.

Bolts or screws or rivets 10, 11 pass thru holes 8, 9 and secure the propeller to the branches 5, 6.

I may also reinforce the engine shaft or shaft extension 4 in the region of the bifurcation by a ring 12, Fig. 4, or by an enlargement 13, Fig. 5, or by any other and convenient means. Also, as shown in Fig. 4, I may reinforce the attachment of branches 5, 6 to blades 1, 2 by a central clamping means 14. Such clamping means preferably comprises a bolt 15 passing thru propeller 1 with Washers 16 overlapping branches 5, 6, one on each side of the propeller, and firmly set up.

Preferably the branches 5, 6 are bent laterally in the plane of the slit and also in a plane at 90 from the plane of the slit as shown in Fig. 5, in which case the branches are appropriately flattened as by hammering or-forging in order to afford a proper contact With the faces of the propeller, and to accommodate conveniently the bolt holes 8, 9. The central part a0, as illustrated, is

preferably of plate-like form with a crosssection wide in the axial plane and relatively narrow in a direction at right-angles thereto, altho I do not confine myself to a central cross-section thus relatively dimensioned. hlorcover, it is not absolutely essential that the propeller per se be made of metal as it may conceivably be made of wood or other material.

What is claimed is:

1. In an attachment for aeronautical propellers, a drive shaft bifurcated at its outer end to receive in the crotch of the bifurcation that part of the propeller in the region of its rotation axis, said drive shaft having its branches bent in opposite directions, and each branch so attached to the propeller at equal radii from said axis as to give adequate resistance to the maximun'i thrust and torque to be experienced by the propeller in the service for which it is designed.

2. In an attachment for aeronautical propellers a drive shaft bifurcated at its outer end to receive in the crotcn of the bifurcation that part of the propeller in the region of its rotation axis, said drive shaft having its branches bent in opposite directions and each branch having a su'fiicient cross-section al area and being so attached to said propeller at equal radii from said axis as to give adequate resistance to the maximum. thrust and torque to be experienced by the propeller in the ser *ice for which it is designed, as well as to insure constancy of pitch angle of the propeller blades.

3. In an attachment means for a one-piece metal aeronautical propeller a drive shaft bifurcated at its outer end to receive in the crotch of the bifurcation that part of the propeller in the region of its rotation axis, said drive shaft having its branches bent in opposite directions and each branch having a sulficient cross-sectional area and being so attached to said propeller at equal radii from said axis as to give adequate resistance to the maximum thrust and torque to be experienced by the propeller in the service for which it is designed, as well as to insure constancy of pitch angle of the propeller blades.

4. A bifurcated. drive shaft extension for an aeronautical engine, having its branches bent laterally in opposite directions and supporting in the crotch of the bifurcation an aeronautical propeller.

5. A split drive shaft extension for an aeronautical engine having its integral branches bent laterally in opposite directions and supporting therebetween an aeronautical propeller.

6. A bifurcated. drive shaft extension for an aeronautical engine supporting in the crotch of the bifurcation an aeronautical propeller, and reinforcing means to fortify said crotch.

7. A longitudinally split drive shaft extension for an aeronautical engine supporting in the crotch of the bifurcation a twoblade aeronautical propeller, the branches of the bifurcation engaging with and being fastened, one each, to and on opposite sides of one each of the propeller blades.

8. A bifurcated drive shaft extension for an aeronautical propeller having its branches bent laterally in opposite directions and supporting in the crotch 0f the bifurcation an aeronautical propeller, means for fastening each said branch to said propeller at points laterally removed from the rotation axis of said propeller, and a clamping means for reinforcing said attachment means.

9. In combination, an aeronautical propeller, and a longitudinally split drive shaft extension Within the embrace of which said propeller is securely fastened.

In testimony whereof I hereunto afiix my signature.

SYLVANUS A. REED. 

